I. Technical Field
The present invention relates to mammographic equipment. More particularly, the present invention relates to a breast compression apparatus having a perforation matrix through which a needle is inserted to identify the location of breast lesions.
II. Background Art
Special roentgenography, or x-ray, techniques for photographically studying the mammary gland, or breast, have resulted in more frequent success in detecting small, non-palpable breast lesions that require excisional biopsy. Breast lesions detectable by x-ray techniques may include carcinoma, calcification, proliferative changes, fibroadenomas, fibrocystic changes or normal tissues. Biopsy of lesions in the initial non-palpable phase is vital to improving treatment effectiveness.
If mammograms reveal a suspicious non-palpable lesion, they may be followed up by a localization procedure which is performed shortly before surgery. The localization procedure generally includes compressing the breast having the non-palpable lesion in a vice-like compression device having a perforation grid. A needle is inserted through one of the perforations and an x-ray is taken with the needle implanted in the general vicinity of the lesion. The x-ray film is then developed while the patient remains in the breast compression device until it is determined whether the needle is accurately placed at the lesion. If the initial location is wrong, the needle is re-implanted and the process is repeated until the lesion is located. Due to the pain and length of time that the breast must be maintained in the compression device, only two or three attempts to locate the lesion are generally tolerable in a single session. When the lesion is located by the needle, a J-shaped marker wire may be inserted through the needle to encircle the lesion. The needle may then be removed and the biopsy performed by a surgeon using the marker wire as a guide to locate and excise the lesion.
Breast compression devices may be applied to permit a medial, or lateral, approach or more usually cranial, or vertical, approach. In either, the breast must remain stationary relative to the perforation grid which necessitates that the patient stay in a fixed position while the localization technique is performed and the x-ray film is developed. If two or more insertions are required, remaining immobile can become increasingly uncomfortable.
An example of a compression device used in needle localization is described in Tabar, Laszlo and Peter V. Dean, "The Investigation of Lesions of the Breast", American Clinics of North America, Vol. XVII No. 3 (December 1979), pp. 616-7. The compression plate for preoperative localization of breast lesions disclosed therein comprises a rigid "Plexiglass", a trademark of Rohm and Haas, for thermoplastic polymethyl methacrylate-type polymers, plate which is held by mechanical claping means between the compression plate and a base plate. Both the compression plate and the base plate are secured to the mammographic equipment and the patient is expected to remain immobile during the localization procedure.
A further development of compression devices for preoperative localization is described in Goldberg, Ronald P., Ferris M. Hall, Morris Simon, "Preoperative Localization of Non-Palpable Breast Lesions Using a Wire Marker and Perforated Mammographic Grid", Radiology 146:833-835, March 1983. The compression device disclosed therein has a perforated grid comprising a freestanding apparatus made of "Plexiglass" that is usable with standard mammographic x-ray equipment. Two base plates form a tunnel into which mammographic film can be inserted while the breast is held compressed. The breast is positioned between the tunnel and the upper "Plexiglass" plate which has multiple perforations that are arranged as a centimeter grid. Some of the perforations are marked with a lead-containing paint so that they can be identified both visually and radiographically. The top plate may be adjusted to change the amount of compressive force applied and to allow for breasts of different sizes. The top plate is fixed in position by a set of detachable bull dog clamps that attach to four threaded rods extending upwardly from the base plates. The device is usable in either the lateral or cranial orientation.
The primary disadvantage with the above devices is their rigidity and the lack of comformability of the pressure plate which results in discomfort. Clamp or vice-like compression force applying mechanisms also add to discomfort and rely solely upon the application of compression to prevent slippage. The compression plate and base generally are smooth planar members that do not conform to the body. Movement of the breast within the compression device is a serious problem, especially if the compression force is not sufficient.
The breast compression and needle localization devices should be sterilized between uses, at least those portions which contact the breast. If the breast compression device is an integral part of the mammographic equipment, sterilization requires disassembly of the device from the machine. Sterilization of the perforated needle localization plate is particularly important and cannot be done without disassembly of the equipment.
Another disadvantage of breast compression and needle localization devices which are incorporated as an integral part of the mammographic equipment is that the patient must remain at the machine during the plate development process and usage of the machine cannot be shared with other patients.
These and other disadvantages are overcome and problems are solved by the present invention's provision of an improved breast compression apparatus including a needle localization matrix as summarized below.